clj-rhino

a nice wrapper to handle rhino from clojure

who?

marianoguerra

why?

the java api for rhino is not really nice

how?

go to clojars page for instructions:

https://clojars.org/org.marianoguerra/clj-rhino

you can see the tests for some usage, here are some REPL examples:

user=> (require '[clj-rhino :as js])
nil
user=> (def sc (js/new-safe-scope))
#'user/sc
user=> (js/eval sc "1 + 1")
2
user=> (js/eval sc "a = 1 + 1")
2
user=> (js/get sc "a")
2
user=> (js/get sc "b")
#<UniqueTag org.mozilla.javascript.UniqueTag@172897f: NOT_FOUND>
user=> (js/undefined? (js/get sc "b"))
true
user=> (js/get sc "b" :w00t?)
:w00t?
user=> (js/defined? (js/get sc "b"))
false
user=> (js/set! sc "b" 42)
nil
user=> (js/defined? (js/get sc "b"))
true
user=> (js/get sc "b" :w00t?)
42
user=> (js/eval sc "a = {name: 'spongebob'}")
#<NativeObject [object Object]>
user=> (js/get-in sc [:a :name])
"spongebob"
user=> (js/get-in sc [:a :age])
#<UniqueTag org.mozilla.javascript.UniqueTag@172897f: NOT_FOUND>
user=> (js/get-in sc [:a :age] :dont-know)
:dont-know
user=> (def compiled-fun (js/compile-function sc "function (a, b) { return a + b; }" :filename "foo.js"))
#'user/compiled-fun
user=> (js/set! sc "add" compiled-fun)
nil
user=> (js/eval sc "add(1, 3)")
4.0

handy convertions:

user=> (def get-field (js/compile-function sc "function getField(obj, field) { return obj[field]; }"))
#'user/get-field

user=> (js/set! sc "getField" get-field)
nil

user=> (js/set! sc "obj" (js/with-context #(js/to-js {:name "spongebob"} sc %)))
nil

user=> (js/eval sc "getField(obj, 'name')")
"spongebob"

user=> (js/eval sc "o = {name: 'spongebob', friends: ['patrick', 'sandy']};")
#<NativeObject [object Object]>

user=> (js/from-js (js/eval sc "o = {name: 'spongebob', friends: ['patrick', 'sandy']};"))
{:friends ["patrick" "sandy"], :name "spongebob"}

exposing clojure functions to rhino:

user=> (require '[clj-rhino :as js])
nil

user=> (defn add [ctx scope this [a b]] (+ a b))
#'user/add

user=> (def scope (js/new-safe-scope))
#'user/scope

user=> (js/set! scope "add" (js/make-fn add))
nil

user=> (js/eval scope "add(1, 2)")
3.0

exposing objects with functions:

user=> (require '[clj-rhino :as js])
nil

user=> (defn add [ctx scope this [a b]] (+ a b))
#'user/add

user=> (defn mul [ctx scope this [a b]] (* a b))
#'user/mul

user=> (def scope (js/new-safe-scope))
#'user/scope

user=> (def api {:add add :multiply mul})
#'user/api

user=> (js/with-context (fn [ctx]
  #_=>   (js/set! scope "api" (js/to-js api scope ctx))
  #_=>   (js/eval scope "api.add(1, 2) + api.multiply(2, 3)")))
9.0

or if you don't need the internal parameters:

(js/with-context
  (fn [ctx]
    (let [scope (js/new-safe-scope)
          add (fn [a b] (+ a b))]

      (js/set! scope "add" (js/wrap-plain-fn add))
      (js/eval scope "add(1, 2)") 3.0)))

execute code with timeout:

(def scope (js/new-safe-scope))
(js/eval-timeout scope "while (true);" 1000)

; will throw a Error exception

call function with timeout:

user=> (def f (js/compile-function scope "function () { while(true); }"))
#'user/f
user=> (js/call-timeout scope f 1000)
TimeOutError
org.marianoguerra.rhino.TimedContextFactory.observeInstructionCount
(TimedContextFactory.java:47)

; function that doesn't timeout
user=> (def f1 (js/compile-function scope "function (a, b) { return a +
b; }"))
#'user/f1
user=> (js/call-timeout scope f1 1000 1 3)
4.0

license?

it seems the clojure people under this circumstances say something like:

Copyright © 2013 marianoguerra

Distributed under the Eclipse Public License, the same as Clojure.